Manufacture of 2,6-dialkyl-3-substituted-6-(beta-cyanoethyl-cyclohexene-(2)-one and products

ABSTRACT

WHERE R1 and R2 are alkyl of from one to five carbons with acrylonitrile in the presence of an alkaline catalyst and inert solvent to form I and contacting I with an aqueous metal hydroxide to form II. 2,6-dialkyl-3-amino-6-(beta-cyanoethyl)-cyclohexene-(2)-one (I) and 2,6-dialkyl-3-hydroxy-6-(beta-carboxyethyl)-cyclohexene-(2)one (II) and manufacture comprising contacting a dialkyl ketone of the general formula:   D R A W I N G

United States Patent Cherubim et al.

[451 Sept. 18,1973

MANUFACTURE or 2,6-D!ALKYL-3-SUBSTlTUTED-6-(BETA-CYANOETHYL-CYCLOHEXENE-(2)-0NE AND PRODUCTS I Inventors: MartinCherubim,

Rhe'inkamp-Erick; Faisal Abo Dagga, Rheinkamp-Utfort, both of GermanyAssignee: Dentsche Texaco Aktiengesellschaft,

Hamburg, Germany,

Filed: Mar. 3, 1971 Appl. No.: 120,728

Foreign Application Priority Data '(2)-one (l) and 3,445,502 5/1969Brown ct al. 260/464 X OTHER PUBLICATIONS Bruson, et al., J.A.C.S., 64(1942) pp. 2850-2858.

Primary Examiner-Joseph P. Brust Attorney-Thomas H. Whaley and Carl G.Ries 57] ABSTRACT 2,6-dialkyl-3-amino-6-(beta-cyan'oethyi) cyclohexene-2,6-dialkyl-3-hydroxy-6-(betacarboxyethyl)-cyclohexene-(2)-one (Ii) andmanufacture comprising contacting a dialkyl ketone of the generalformula:

0 R -CHr -CHrR;

V where R and R are alkyl of from one to five carbons with acrylonitrilein the presence of an alkaline catalyst and inert solvent to form I andcontacting I with an aqueous metal hydroxide to form ll.

4 Claims, No Drawings MANUFACTURE OF 2,6-D'lALKYL-3-SUBSTlTUTED-6-(BETA-CYANOETHYL-CYCLOHEXENE-(2)-ONE AND PRODUCTS Surprisingly, it was foundthat 2,6-dialkyl-3- amino- I o-(fi-cyanoethyl)-cyclohexene-2-onesrepresented y the structural formula O newts-cm N R1 NHa where R, and R,are equal or different alkyl and have from one to five carbon atoms, maybe obtained by reacting dialkyl ketone represented by the structuralformu la:

where R, and R, are as heretofore defined, with acrylo-- nitrile in thepresence of a basic catalyst in the molar ratio of from 5:1 to 1:4 in300 to 5,000 grams of solvent per mole of acrylonitrile at temperaturesranging from 0 to 150C.

Specific examples of said dialkyl ketone reactant are where R, and R,are methyl; R, is methyl and R, is propyl; and R, is ethyl and R, isisopentyl.

Preferred conditions include a dialkyl ketone to acrylonitrile molarratio of from 3:1 to 1:2 in 500 to 3,000 grams of solvent per mole ofacrylonitrile in the presence of an alkali metal hydroxide and/or alkalimetal alcoholate.

The catalysts to be added-may include basic compounds such ashydroxides, alcoholates or other alkaline compounds, in amounts of 0.005to 0.5 mole per mole of acrylontrile. Specific examples are sodiumhydroxide, potassium hydroxide, sodium methylate, potassium ethylate,and sodium t-butylate. As noted above alkanolates may be employed. Themost favornamely able results were obtained with 0.01 to 0.2 mole ofalphatic 'and aromatic hydrocarbons and mixtures thereof. The bestresults were obtained with tertiary butanol.

By hydrolysis of the NH,- and CN-groups of the DACO using for exampleaqueous alkali metal hydroxides (e.g., sodium hydroxide, potassiumhydroxide) other compositions not yet known were obtained,

2,6-dialkyl-3-hydr0xy-o-(fi-carboxyethyl)- cyclohexene-(2)-ones (DHCO).The hydrolysis is conducted at between about 50 and C. until theevolution of ammonia ceases, e.g. 2-50 hours. Advantageously, the alkalimetal hydroxide is employed as a 5 to 20 wt. percent aqueous solution ina mole ratio of between about 0.1 to 1 mole DACO per mole alkali metalhydroxide.

The composition and structure of the compounds of the invention wereestablished by carbon, hydrogen,

and nitrogen (CHN) analyses, identification of the functional groups,chemical analyses, UV-, IR, NMR- and mass spectrometry and thedetermination of the molecular weights.

' Specific examples of the product derivative contemplated herein arewhere R, and R are methyl; R, is methyl and R, is propyl; and R, isethyl and R, is isopentyl.

The compositions prepared according to this invention may be used asintermediate products for organic syntheses, such as for instance theproduction of cyclic amino-acids, esters, hydroxy acids and epoxidecompounds, they may be used as intermediates in the production ofpolyamides, alkyd and ketone resins and also as modifying and curingagents for phenolic and epoxide resins. They are also useful asadditives to lubricating oil and starting material for detergents.

The following examples are to illustrate the present invention withoutlimiting the scope thereof:

EXAMPLE I Preparation of 2,6-dimethyl-3-amino-6-(ficyanoethyl)-cyclohexene-(2-one.

323 grams is diethyl ketone (3.75 moles), 199 grams of acrylonitrile(3.75 moles) and 5,320 grams of tert.- butanol are refluxed withvigorous stirring under addition of 63 ml of a 10 percent aqueouspotassium hydroxide solution. After 3 hours the reaction is terminated.The reaction mixture is removed by suction from the precipitatedcrystals of the 2,2,4-tri-(fi-cyanoethyl)-diethyl ketone. The motherliquor is diluted with distilled water, the p -value is adjusted toabout 5 by means of concentrated hydrochloric acid, followed byextraction with chloroform. The aqueous phase is extracted with CHCl,two more times. The combined chloroform extracts were dried over sodiumsulphate, filtered off and concentrated. The evaporation residue isdissolved in ethyl acetate. The crystals precipitated in the cold arerecrystallized from ethyl acetate. 206

grams of 2,6-dimethyl-3-amino-6-(B-cyanoethyl)- cyclohexene-(2)-one areobtained. Iodine number:

calculated 264.8 found 266 Yield: 57.2 percent of theory Melting point:156 to 158C. CHN analysis:

C H N molec. weight calc. 68.7% 8.4% 14.6% 192.85 found 68.7% 8.6% 14.8%194 EXAMPLE 11 Preparation of2,6-dimethyl-3-hydroxy-6-(ficarboxyethyl)-cyclohexene-(2)-one.

75 grams (0.39 mole) of2.6-dimethyl-3-amino-6-(ficyanoethyl)-cyclohexene-(2)-one are dilutedwith 600 ml of a percent aqueous potassium hydroxide solution andrefluxed until no more ammonia separates. This saponification takesabout 30 hours. The mixture is then acidified with hydrochloric acid toa p -value of between 2 and 3. The precipitating crystals are removed bysuction and washed with cold water. The product which is relatively purenow is recrystallized from dichloroethane or water. 76 grams of 2,6-dimethyl-3-hydroxy-6-(,B-carboxyethyl)-cyclohexene- (2)-one are obtainedhaving a melting point of between 161 and 163C. The yield is 92 percentof theory.

We claim:

1. Process for the production of 2,6-dialkyl-3-amino-6-(B-cyanoethyl)-cyclohexene(2)-ones represented by the general formula:

NCCH1CH R1 R2 where R and R are the same or different alkyl of from oneto five carbons, which comprises reacting a ketone having the generalformula:

where R, and R, are as heretofore defined with acrylonitrile in a molarratio ranging from 5:1 to 1:4 in 300 to 5,000 grams of an inert liquidsolvent per mole of acrylonitrile in the presence of an alkalinecatalyst selected from the group consisting of alkali metal hydroxideand alkali metal alkanolate at temperatures ranging from 0 to C., saidcatalyst being present in an amount between 0.005 and 0.5 mole catalystper mole acylonitrile.

2. The process according to claim 1, characterized in that the dialkylketones are reacted with acrylonitrile in a molar ratio ranging from 3:1to 1:2 in 500 to 3,000 grams of a solvent per mole of acrylonitrile.

3. The compound of 2,6-dialkyl-3-amino-6-(B-cyano-ethyl)-cyclohexene-(2)-one, having the general formula NC-CH -CH;R1

where R and R, are equal or different alkyl and have from one to fivecarbon atoms.

4. The compound according to claim 3 wherein R and R are methyl.

2. The process according to claim 1, characterized in that the dialkylketones are reacted with acrylonitrile in a molar ratio ranging from 3:1to 1:2 in 500 to 3,000 grams of a solvent per mole of acrylonitrile. 3.The compound of 2,6-dialkyl-3-amino-6-( Beta-cyano-ethyl)-cyclohexene-(2)-one, having the general formula
 4. Thecompound according to claim 3 wherein R1 and R2 are methyl.